can canyone here help me with this physics problem: Air moving at 11.0 m/s in a steady winds encounters a windmill of diameter 2.3m and having an efficiency of 27.5 %. The energy generated by the windmill is used to pump water from a well 32.5m deep into a tank 2.30m above the ground. At what rate in liters per minute can water be pumped into the tank? This is what I have so far: Ekin = 1/2mv^2 Density for air is: 1.29 kg/m^3 The time for this energy to form is 1 sec. m = ( a * v * A ) ..... where A is air density and v is velocity, a in this case is area of the windmill, which is pi(diameter/2)^2 Thus Ekin = 1/2 (a * v * A) So : Ekin * 25% = energy generated by the windmill After that, I'm lost. But I think it has to do something with potential energy.